US20050238084A1

US20050238084A1 - Method and system for operating multiple dependent networks

Info

Publication number: US20050238084A1
Application number: US11/043,457
Authority: US
Inventors: Yefim Kuperschmidt; Shor Gadi
Original assignee: Wisair Ltd
Current assignee: Wisair Ltd
Priority date: 2004-01-08
Filing date: 2005-01-25
Publication date: 2005-10-27
Also published as: US20050237965A1; WO2005065035A3; US20050238025A1; WO2005065035A2; US20050237964A1; US7496064B2; US7936774B2; US20050249183A1; US20050237956A1

Abstract

A device and method for ultra wide band transmission, the method includes: (a) allowing a first group of ultra wide band devices to exchange information using a first frequency hopping sequence; and (b) allowing at least one certain device that is responsive to at least one transmission of information from a device of the first group to exchange information using the first frequency hopping sequence during at least one time period and allowing devices that belong to the second group to exchange information using a second frequency hopping sequence during at least one other time period.

Description

RELATED APPLICATIONS

The present patent application is a continuation application of International Application No. PCT/IL05/000021 filed Jan. 96, 2005, which claims priority benefit from U.S. Provisional Application No. 60/535,436 filed Jan. 8, 2004 and U.S. Provisional Application No. 60/535,621 filed Jan. 8, 2004, the contents of which are incorporated herein by reference.
This application is related to the following applications:

1. METHOD AND DEVICES FOR MULTICASTING INFORMATION OVER A NETWORK THAT APPLIED A DISTRIBUTED MEDIA ACCESS CONTROL SCHEME, application Ser. No. ______, filed Jan. 25, 2005.
2. METHODS AND DEVICES FOR EXPANDING THE RANGE OF A NETWORK, application Ser. No. ______, filed Jan. 25, 2005.
3. A DEVICE AND METHOD FOR MAPPING INFORMATION STREAMS TO MAC LAYER QUEUES, application Ser. No. ______, filed Jan. 25, 2005.
4. ULTRA WIDE BAND WIRELESS MEDIUM ACCESS CONTROL METHOD AND A DEVICE FOR APPLYING AN ULTRA WIDE BAND WIRELESS MEDIUM ACCESS CONTROL SCHEME, application Ser. No. ______, filed Jan. 25, 2005.
5. METHOD AND DEVICE FOR TRANSMISSION AND RECEPTION OVER A DISTRIBUTED MEDIA ACCESS CONTROL NETWORK, application Ser. No., filed Jan. 25, 2005.

FIELD OF THE INVENTION

The invention relates to methods and device for operating multiple dependent networks and especially multiple adjacent ultra wide band networks.

BACKGROUND OF THE INVENTION

Recent developments in telecommunication and semiconductor technologies facilitate the transfer of growing amounts of information over wireless networks.
The demand for short to medium range, high speed connectivity for multiple digital devices in a local environment continues to rise sharply. For example, many workplaces and households today have many digital computing or entertainment devices such as desktop and laptop computers, television sets and other audio and video devices, DVD players, cameras, camcorders, projectors, handhelds, and others. Multiple computers and television sets, for instance, have become common in American households. In addition, the need for high speed connectivity with respect to such devices is becoming more and more important. These trends will inevitably increase even in the near future.
As the demand for high speed connectivity increases along with the number of digital devices in typical households and workplaces, the demand for wireless connectivity naturally grows commensurately. High-speed wiring running to many devices can be expensive, awkward, impractical and inconvenient. High speed wireless connectivity, on the other hand, offers many practical and aesthetic advantages, which accounts the great and increasing demand for it. Ideally, wireless connectivity in a local environment should provide high reliability, low cost, low interference caused by physical barriers such as walls or by co-existing wireless signals, security, and high speed data transfer for multiple digital devices. Existing narrowband wireless connectivity techniques do not provide such a solution, having problems such as high cost, unsatisfactory data transfer rates, unsatisfactory freedom from signal and obstacle related interference, unsatisfactory security, and other shortcomings. In fact, the state of the art does not provide a sufficiently satisfactory solution for providing high speed wireless connectivity for multiple digital devices in a local environment.
The state of the art in wireless connectivity generally includes utilization of spread spectrum systems for various applications. Spread spectrum techniques, which spread a signal over a broad range of frequencies, are known to provide high resistance against signal blocking, or “jamming,” high security or resistance against “eavesdropping, ” and high interference resistance. Spread Spectrum techniques have been used in systems in which high security and freedom from tampering is required. Additionally, Code Division Multiple Access (CDMA), a spread spectrum, packet-based technique, is used in some cellular phone systems, providing increased capacity in part by allowing multiple simultaneous conversation signals to share the same frequencies at the same time.
Known spread spectrum and modulation techniques, including CDMA techniques, direct sequence spread spectrum (DSSS) techniques, time hopping spread spectrum (THSS) techniques, and pulse position modulation (PPM) techniques, do not satisfactorily provide wireless connectivity in a local environment, including high reliability, low cost, low interference, security, and high speed data transfer for multiple digital devices. In addition, known UWB transmission and communication methods and systems lack satisfactory quality in areas that can include flexibility, adaptivity and adaptive trade-off capabilities in areas such as power usage, range, and transfer rates, and low cost implementation.
A number of U.S. and non-U.S. patents and patent applications discuss spread spectrum or UWB related systems for various uses, but are nonetheless in accordance with the above described state of the art. The U.S. and non-U.S. patents and patent applications discussed below are hereby incorporated herein by reference in their entirety.
There are several Japanese patents and applications in some of these areas. Japanese patent application JP 11284599, filed on Mar. 31, 1998 and published on Oct. 15, 1999, discusses spread spectrum CDMA mobile communications. Japanese patent application JP 11313005, filed on Apr. 27, 1998 and published on Nov. 9, 1999, discusses a system for rapid carrier synchronization in spread spectrum communication using an intermittently operative signal demodulation circuit. Japanese patent application JP 11027180, filed on Jul. 2, 1997 and published on Jan. 29, 1999, and counterpart European application EP 0889600 discuss a receiving apparatus for use in a mobile communications system, and particularly for use in spread spectrum Code Division Multiple Access communications between a base station and a mobile station. Japanese patent application JP 21378533, filed on Nov. 18, 1988 and published on May 25, 1990, discusses a transmitter for spread spectrum communication.
A number of U.S. patents and published applications discuss spread spectrum or UWB in various contexts. U.S. Pat. No. 6,026,125, issued Feb. 15, 2000 to Larrick, Jr. et al., relates to utilization of a carrier-controlled pulsed UWB signal having a controlled center frequency and an adjustable bandwidth. U.S. Pat. No. 6,351,652, issued Feb. 6, 2002 to Finn et al., discusses impulse UWB communication. U.S. Pat. No. 6,031,862, issued Feb. 29, 2000 to Fullerton et al., and related patents including U.S. Pat. Nos. 5,677,927, 5,960,031, 5,963,581, and 5,995,534, discuss a UWB communications system in which impulse derived signals are multiplied by a template signal, integrated, and then demodulated, to increase the usability if signals which would otherwise be obscured by noise. U.S. Pat. No. 6,075,807, issued Jun. 13, 2000 to Warren et al., relates to a spread spectrum digital matched filter. U.S. Pat. No. 5,177,767, issued Jan. 5, 1993 to Kato, discusses a “structurally simple” wireless spread spectrum transmitting or receiving apparatus which is described as eliminating the need for code synchronization. U.S. Pat. No. 6,002,707, issued Dec. 14, 1999 to Thue, relates to radar system using a wide frequency spectrum signal for radar transmission to eliminate the need for very high energy narrow pulse transmitter and receiver systems. U.S. Pat. No. 5,347,537, issued Jun. 21, 1994 to Mori, et al., and related patents including U.S. Pat. Nos. 5,323,419 and 5,218,620, discuss a direct sequence spread spectrum transmitter and receiver system. U.S. Pat. No. 5,206,881, issued Apr. 27, 1993, discusses a spread spectrum communication system attempting to use rapid synchronization of pseudo-noise code signals with data packet signals.
A number of published PCT international applications also discuss spread spectrum or UWB in various contexts. PCT international application, publication number WO 01/39451 published on May 31, 2001, discusses a waveform adaptive transmitter for use in radar or communications applications. PCT international application, publication number WO 01/93441, published on Dec. 6, 2001, discusses a UWB high-speed digital communication system using wavelets or impulses. PCT international application, publication number WO 01/99300, published on Dec. 27, 2001, discusses wireless communications using UWB signaling. PCT international application, publication number WO 01/11814, published on Feb. 15, 2001, discusses a transmission method for broadband wired or wireless transmission of information using spread spectrum technology.
Short-range ultra wide band wireless networks are being developed in order to allow wireless transmission of vast amounts of information between various devices. U.S. patent application 2003/0063597 of Suzuki, titled “Wireless transmission system, wireless transmission method, wireless reception method, transmitting apparatus and receiving apparatus”, which is incorporated herein by reference, described wireless networks that each includes a base station. U.S. patent application 2004/0170217 of Ho titled “Wireless personal area networks with rotation of frequency hopping sequences” describes a multiple piconets (personal network) environment in which each piconets is controlled by a piconets coordinator. Non-related and non-synchronized piconets use rotating frequency hopping sequences in order to avoid interferences.
Some of short-range ultra wide band wireless networks are characterized by a distributed architecture in which devices exchange information without being controlled by a central host or a base station.
FIG. 1 is a schematic illustration of two ultra wide band wireless networks (also referred to as personal access networks) 10 and 20, each including multiple devices that wirelessly communicate with each other. First network 10 includes first till third devices A-C 11-13 and the second network 20 includes forth till sixth devices D-F 24-26.
FIG. 2 illustrates a typical TDMA frame 30. TDMA frame 30 includes multiple time-slots, such as beacon slots 14 and media access slots. The media access slots include distributed reservation protocol (DRP) slots 36 and prioritized contention access (PCA) slots 38. PCA slots are also referred to as PCA periods. DRP slots are also referred to as DRP periods.
The beacon slots are used to synchronize devices to the TDMA frame 30. A typical beacon frame includes information that identifies the transmitting device. It also may include timing information representative of the start time of the TDMA frame 30.
The DRP slots 36 are coordinated between devices that belong to the same network and allow devices to reserve these slots in advance. During the PCA slots 38 devices that belong to the network compete for access based upon their transmission priority. It is noted that the allocation of media access time slots is dynamic and can change from one TDMA frame to another.
Typically, transmissions from devices during PCA slots are assigned by applying a carrier sense multiple access with collision avoidance (CSMA/CA) scheme If a device requests to transmit over a wireless medium it has to check if the wireless medium is idle. If the wireless medium is idle, the device has to wait a random backoff period. This random backoff time is selected from a contention window that has a length that is related to the priority of the device. For higher-priority devices the contention window is shorter.
The transmission process is usually quite complex and includes many operations such as but not limited to forward correction encoding, interleaving, modulating and the like. A receiver must reverse the procedures applied by the transmitter.
FIG. 3 illustrates a parent network 5100 and a child network 5200. Each of these networks is also referred to as a piconet. The parent network 5100 includes a first group of ultra wide band devices 5102-5120. The parent network 5100 includes a management device 5110 that controls the exchange of information between the devices of the parent network, by applying a time division multiplex access scheme. The child network includes a second group of devices 5120 and 5202-5206. Device 5120 belongs to both the parent and child networks 5100 and 5200 respectively. It controls the exchange of information between the devices of the second network 5200.
Transmission between devices that belong to the parent network 5100 can be subjected to interferences from devices of the child network 5200 and vice versa. There is a need to provide an efficient manner for solving this interference issue.

SUMMARY OF THE INVENTION

An ultra wide band device that includes: a receiver adapted to receive information from at least one device of a first group of ultra wide band devices, using a first frequency hopping sequence; and a transmitter, adapted to transmit information to at least one device of the first group of ultra wide band devices, using the first frequency hopping sequence during at least one time period and further adapted to transmit information to at least one device of a second group of ultra wide band devices, using a second frequency hopping sequence, during at least one other time period.
A method for ultra wide band transmission, the method includes: (a) allowing a first group of ultra wide band devices to exchange information using a first frequency hopping sequence; and (b) allowing at least one certain device that is responsive to at least one transmission of information from a device of the first group to exchange information using the first frequency hopping sequence during at least one time period and allowing devices that belong to the second group to exchange information using a second frequency hopping sequence during at least one other time period.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be understood and appreciated more fully from the following detailed description taken in conjunction with the drawings in which:
FIG. 1 is a schematic illustration of two networks (also referred to as personal access networks), each including multiple devices that wirelessly communicate with each other;
FIG. 2 illustrates a typical TDMA frame;
FIGS. 4-5 illustrate a device capable of wireless transmission, and some of its components, according to an embodiment of the invention;
FIG. 6 illustrates a parent network TDMA frame and a neighbor TDMA frame;
FIG. 7 illustrates a parent network TDMA frame and a child TDMA frame;
FIG. 8 illustrates the multiple band groups allocated for ultra wide band transmission;
FIG. 9 illustrates a first frequency hopping sequence;
FIG. 10 illustrates a parent network TDMA frame and an affected network TDMA frame according to an embodiment of the invention;
FIG. 11 illustrates a first frequency hopping sequence and a second frequency hopping sequence, according to an embodiment of the invention;
FIG. 12 illustrates a first frequency hopping sequence and a second frequency hopping sequence, according to another embodiment of the invention;
FIG. 13 is a flow chart of a method for ultra wide band transmission, according to an embodiment of the invention; and
FIG. 14 illustrates a ultra wide band (UWB) device according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

Some portions of the following description relates to wireless ultra wide band networks that utilize a distributed media access control scheme. In these networks there is no central media access controller, but rather various devices of the network participate in determining how to share a common wireless medium. It is noted that according to various embodiments of the invention the disclosed methods and devices can be applied in networks that utilize a distributed media access control scheme but differ from ultra wide band wireless networks. It is further noted that according to some embodiments of the invention networks other than ultra wide band network can apply some of the suggested methods.
Various operations such as transmissions utilize the distributed media access control scheme in the sense that the access to a shared medium is governed by a distributed media access control scheme.
Some embodiments of the invention provide an ultra wide band wireless medium access control method and a device capable of performing ultra wide band wireless medium access control schemes.
Conveniently, the device is a part of a ultra wideband wireless network and has a communication protocol stack that includes at least a PHY layer and a MAC layer. The MAC layer of such devices controls the access to ultra wide band wireless medium and is referred to ultra wide band wireless medium access control.
Examples of devices that have a PHY layer are illustrated in the following U.S. patent applications, all being incorporated herein by reference: U.S. patent application Ser. No. 10/389789 filed on Mar. 10 2003 and U.S. patent application Ser. No. 10/603,372 filed on Jun. 25 2003.
The receiver can include various components that are arranged in multiple layers. A first configuration includes a frame convergence sub-layer, a MAC layer, a PHY layer as well as MAC SAP, PHY SAP, frame convergence sub-layer SAP and a device management entity can also be utilized. Another configuration is described at FIGS. 4 and 5.
Wisair Inc. of Tel Aviv Israel manufactures a chip set that includes a Radio Frequency PHY layer chip and a Base-Band PHY layer chip. These chips can be connected in one end to a RF antenna and on the other hand be connected or may include a MAC layer circuitry.
FIG. 4 illustrates a device 60 that is capable of wireless transmission, according to an embodiment of the invention.
Device 60 includes antenna 61 that is connected to a RF chip 62. RF chip 62 is connected to a MAC/PHY layers chip 63 that includes a PHY layer block 63 and a MAC layer block 64. The MAC/PHY layers chip 63 is connected to an application entity 66 that provides it with information to be eventually transmitted (TX) and also provides the application 66 with information received (RX) by antenna 61 and processed by PHY and MAC layers blocks 68 and 69 of FIG. 5.
Typically, the MAC layer block 64 controls the PHY layer block using a PHY status and control interface. The MAC and PHY layers exchange information (denoted TX and RX) using PHY-MAC interface 90. The RF chip 62 provides to the PHY layer block 63 received information that is conveniently down-converted to base band frequency. The RF chip 62 receives from the PHY layer block 63 information to be transmitted as well as RF control signals. The application 66 is connected to the MAC/PHY layers chip 63 by a high speed I/O interface.
FIG. 5 illustrates various hardware and software components of the MAC/PHY layers chip 63, according to an embodiment of the invention.
The Upper Layer IF block 64 of the MAC/PHY layers chip 63 includes hardware components (collectively denoted 69) and software components (collectively denoted 68). These components include interfaces to the PHY layer (MAC-PHY interface 90) and to the application (or higher layer components).
The hardware components 69 include configuration and status registers 81, Direct Memory Access controller 82, First In First Out (FIFO) stacks 83 and frame validation and filtering components 84, DRP and PCA slots schedulers 85, ACK processors 86, and MAC-PHY internal interface 87.
The software components 68 include a management module 72, transmit module 73, receive module 74 m hardware adaptation layer 75, DMA drivers 76, MAC layer management entity (MLME) service access point (SAP) 71, MACS API 70 and the like.
These software and hardware components are capable of performing various operations and provide various services such as: providing an interface to various layers, filtering and routing of specific application packets sent to MAC data queues or provided by these queues, performing information and/or frame processing, and the like.
The routing can be responsive to various parameters such as the destinations of the packets, the Quality of Service characteristics associated with the packets, and the like.
The processing of information along a transmission path may include: forming the MAC packet itself, including MAC header formation, aggregation of packets into a bigger PHY PDU for better efficiency, fragmentation of packets for better error rate performance, PHY rate adaptation, implementation of Acknowledgements policies, and the like.
The processing of information along a reception path may include de-aggregation and/or de-fragmentation of incoming packets, implementation of acknowledgment and the like.
The hardware components are capable of transferring data between MAC software queues and MAC hardware (both TX and RX), scheduling of beacons slots, scheduling of DRP and PCA access slots, validation and filtering (according to destination address) of incoming frames, encryption/decryption operations, low-level acknowledgement processing (both in the TX path and in the RX path),
Device 60 can be a simple device or even a complex device such as but not limited to a multimedia server that is adapted to transmit information frames of different types to multiple devices. It can, for example transmit Streaming data, like voice, Video, Game applications, etc.) data files during DRP slots, and while PCA slots transmits video over IP frames, download MP3 files, download MPEG-2 files, and stream or download MPEG-4 streams.
Usually, voice frames are associated with higher quality of service requirements and accordingly are given higher transmission priorities. The voice frames QoS requirements are followed by video frames that in turn are followed by lower quality of service requirements (lower priority transmission) frames such as best effort frames and background frames.
Referring to FIG. 3, in order to prevent such interference the devices of the child network are allowed to exchange information during one time period, while the devices of the parent network are allowed to exchange information during another time period. Device 5120 that belongs to both networks is able of exchanging information with devices of the parent group during the one time period or a portion of that one time period. Typically device 5120 is capable of receiving a beacon frame transmitted by the management device 5110 and accordingly to define the transmission window of the child network.
It is noted that the same inefficient use of the wireless medium can occur if the child device is replaced by a neighbor network. A neighbor network does not include a device that also belongs to the parent network, but the transmissions of devices of the neighbor network may interfere with the transmission of devices of the parent network.
FIG. 6 illustrates a parent network TDMA frame 5300 and a neighbor TDMA frame 5400. The parent network TDMA frame 5300 starts by a beacon frame 5310 transmitted by the management device 5110. The beacon frame 5310 may include information that determines which device can transmit during various time slots of the TDMA frame 5300. The beacon frame 5310 is followed by a contention time slot 5312, that is followed by multiple slots CTA_1-CTA_n 5314-5330 that are allocated for a transmission of devices from the parent or neighbor networks.
The second slot CTA_2 is allocated for transmissions of devices of the neighbor network. During this time slot the devices of the parent network (except device 5120) are not allowed to transmit. The neighbor TDMA frame 5400 includes a neighbor beacon frame 5406 and multiple time slots (collectively denoted 5402) during which device of the neighbor network 5200 are allowed to transmit information. These time slots 5402 are followed by a silence period 5404 that starts when CTA_2 of certain parent network TDMA frame 5300 ends and ends when the CTA_2 of the next parent network TDMA frame 5300 starts.
It is noted that the mentioned above as well as the mentioned below TDMA frames are exemplary and that their content can vary from TDMA frame to TDMA frame.
FIG. 7 illustrates a parent network TDMA frame 5300 and a child TDMA frame 5500. The child network TDMA frame 5500 starts by a child network beacon frame 5510 transmitted by device 5210 that acts like a child network management device. The child network beacon frame 5510 may include information that determines which device of the child network can transmit during various time slots of the child network TDMA frame 5500. The child network beacon frame 5510 is followed by a contention time slot 5512, that is followed by multiple slots CCTA_1-CCTA_k 5514-5530 that are allocated for a transmission of devices from the child networks. The last slot CCTA_k 5530 is followed by a silence period.
The second slot CTA_2 is allocated for transmissions of devices of the child network. During this time slot the devices of the parent network (except device 5120) are not allowed to transmit. The child TDMA frame 5500 includes multiple time slots (collectively denoted 5502) during which device of the child network 5200 are allowed to transmit information. These time slots 5502 are followed by a silence period 5504 that starts when CTA_2 of certain parent network TDMA frame 5300 ends and ends when the CTA_2 of the next parent network TDMA frame 5300 starts.
Both child network and neighbor network, as well as other types of networks can be regarded as networks that are affected from the transmissions of the parent network. These transmissions result in a sub-optimal usage of the shared ultra wide band media.
There is a need to provide an efficient method for utilizing the shared ultra wide band media.
FIG. 8 illustrates the multiple band groups 5615-5735 allocated for ultra wide band transmission. The first band group 5615 includes the first till third bands 5610-5630. The second band group 5645 includes the fourth till sixth bands 5640-5660. The third band group 5675 includes the seventh till ninth bands 5670-5690. The fourth band group 5695 includes the tenth till twelfth bands 5700-5720. The fifth band group 5725 includes the thirteenth and the fourteenth bands 5730 and 5740. Each band is 528 Mhz wide. The center frequencies of these bands are: 3432 Mhz, 3960 Mhz, 4488 Mhz, 5016 Mhz, 5544 Mhz, 6072 Mhz, 6600 Mhz, 7128 Mhz, 7656 Mhz, 8184 Mhz, 8712 Mhz, 9420 Mhz, 9768 Mhz and 10296 Mhz.
An ultra wide band device, such any of devices 5202-5206 or 5102-5120, can perform one out of several pre-defined frequency hopping sequences. Each frequency hopping sequence is limited to frequencies within a single band group. Each sequence is associated with a unique Time frequency code. Some codes are allocated for frequency hopping sequences which include a frequency from each band. Other codes are allocated for fixed frequency sequences that include a single frequency.
Before initiating either one of the first or second frequency hopping sequences the receivers and transmitter that are going to use either of these hopping sequence is notified about it. There are various ways to perform such a notification, including sending dedicated messages, synchronization and the like. Conveniently, a transmitter includes information representative of the selected sequence within each information frame he sends. Conveniently, each time frequency code is associated with a unique base time domain sequence and a cover sequence that belong to a packet/frame synchronization sequence that in turn is a part of an information frame PLCP preamble.
FIG. 9 illustrates a first frequency hopping sequence 6000. This frequency hopping sequence 6000 starts by transmitting a first symbol (represented by box 6002) using a carrier frequency from a first band of a certain band group (denoted by “band # 1”). This transmission is followed by a guard period denoted 6004. Guard period 6004 is followed by a transmission of a second symbol (represented by box 6006) using a carrier frequency from a second band of a certain band group (denoted by “band # 2”). This transmission is followed by a guard period denoted 6008. Guard period 6008 is followed by a transmission of a third symbol (represented by box 6010) using a carrier frequency from a third band of a certain band group (denoted by “band # 3”). This transmission is followed by a guard period denoted 6012.
Guard period 6012 is followed by a transmission of a fourth symbol (represented by box 6014) using a carrier frequency from the first band. This transmission is followed by a guard period denoted 6016. Guard period 6016 is followed by a transmission of a fifth symbol (represented by box 6018) using a carrier frequency from the second band. This transmission is followed by a guard period denoted 6020. Guard period 6020 is followed by a transmission of a third symbol (represented by box 6022) using a carrier frequency from the third band. This transmission is followed by a guard period denoted 6024.
An inter-symbol period is defined by the transmission period of that symbol plus the guard time that follows this transmission. Each symbol is usually transmitted during a short time period that is conveniently three hundred nanoseconds long. The guard period is typically about sixty nanoseconds long. Thus an inter-symbol period is conveniently three hundred and sixty nanoseconds.
According to an embodiment of the invention the silence periods are replaced by periods in which the devices of both networks can operate in parallel, but using different frequency hopping sequences, such as not to interfere with each other.
According to an embodiment of the invention the frequency hopping sequences can be substantially the same but be time shifted in relation to each other. According to another embodiment of the invention the first and second frequency hopping sequences differ from each other and are not just a time shifter version of each other.
FIG. 10 illustrates a parent network TDMA frame 5300′ and a affected network TDMA frame 6100 according to an embodiment of the invention.
The parent network TDMA frame 5300′ does not include a silence period, as the transmission of parent network devices do not interfere the transmissions of the affected network devices. The affected network, or at least one device of the affected network is adapted to use the first frequency hopping sequence during a first period 6102 and use a second frequency hopping sequence during a second period 6104. The first period is used to exchange information with the parent network while the second period 6104 is used for exchanging information between devices of the affected network without interfering to the devices of the first network.
FIG. 11 illustrates a first frequency hopping sequence 6000 and a second frequency hopping sequence 6100, according to an embodiment of the invention. The second frequency hopping sequence 6100 equals the first frequency sequence but is delayed by an inter-symbol period. The second frequency hopping sequence 6100 includes the transmissions of multiple symbols (denoted 6102-6122) and multiple guard periods (denoted 6104-6124).
FIG. 12 illustrates a first frequency hopping sequence 6000 and a second frequency hopping sequence 6200, according to another embodiment of the invention. The second frequency hopping sequence 6200 equals the first frequency sequence but is delayed by an half of an inter-symbol period. The second frequency hopping sequence 6200 includes the transmissions of multiple symbols (denoted 6202-6222) and multiple guard periods (denoted 6204-6224).
It is noted that the previous figures illustrate frequency hopping sequences that were limited to a single band group that includes three bands. It is noted that the amount of bands per band group, can be larger than three and that the frequency sequence does not necessarily be limited to frequencies within a single band group.
Those of skill in the art will appreciate that the second frequency hopping sequence can differ from the first frequency, and not just be being a delayed version.
It is noted that at least one device, such as certain device 5120, is capable of monitoring or controlling the second frequency hopping sequence to make sure that the transmissions of the second network devices do not interfere with the transmissions of the first network devices. For example if the frequency hopping sequences differ by a certain delay, that certain device can synchronize to the transmissions of the first network and then introduce a delay between the frequency hopping sequences.
FIG. 13 is a flow chart of a method 6500 for ultra wide band transmission.
Method 6500 starts by stage 6510 of allowing a first group of ultra wide band devices to exchange information using a first frequency hopping sequence. Said allowing may include adjusting at least one device of the first group to perform such an exchange of information, informing one or more device that such a frequency hopping scheme should be implemented, and even when it should be implemented.
Stage 6510 is followed by stage 6520 of allowing at least one certain device that is responsive to at least one transmission of information from a device of the first group to exchange information using the first frequency hopping sequence during at least one time period and allowing devices that belong to the second group to exchange information using a second frequency hopping sequence during at least one other time period.
Conveniently, the at least one certain device belongs to the first and second groups of devices. Conveniently, the at least one certain device only belongs to the second group of devices.
Conveniently, the second frequency hopping sequence is substantially a delayed first frequency hopping sequence. Conveniently, the first and second frequency sequences include hopping between frequencies that belong to the same frequency band group. Conveniently, method 6500 involves controlling the exchange of information between members of the second group by the certain device. Conveniently, method 6500 involves controlling the exchange of information between device of the second group by utilizing a distributed media access control scheme.
Conveniently, method 6500 includes transmitting information representative of the first and second frequency hopping sequences prior to utilizing the first and second frequency hopping sequences.
Conveniently, the first frequency hopping sequence comprises performing a frequency hopping between a transmission of each symbol. Conveniently, the second frequency hopping sequence is substantially a delayed first frequency hopping sequence and wherein the delay is a multiple integer of a inter-symbol period. Conveniently, the second frequency hopping sequence is substantially a delayed first frequency hopping sequence and wherein the delay is fraction of an inter-symbol period.
Conveniently, stages 6510 and 6520 are repeated for allowing a repetition of multiple transmission sessions between members of the first network and multiple transmission sessions between members of the second network.
Conveniently, method 6500 includes synchronizing between the first and second frequency hopping sequences.
Conveniently, the at least one time period comprises a first set of time periods and the at least one other time period comprises a second set of time periods. Conveniently, each time period of the first set is followed by a time period of the second set.
It is further noted that FIGS. 3 and 6-14 refer to a network that includes a management entity that applies a media access control scheme. It is noted that according to an embodiment of the invention at least one of the networks can apply a distributed media access control scheme.
FIG. 14 illustrates a device 5555 according to an embodiment of the invention.
Device 5555 can be substantially similar to device 60 of FIGS. 4-5, or one of the devices of the first and second networks 10 and 20 of either FIG. 1 or 26, or be similar to device 5555 of FIG. 39. And can also be substantially similar to any combination of a receiver and a transmitter illustrated in either one of PCT applications, publication number WO 2004/017547A2 and publication number WO 2004/077684A2 of Wisair Ltd.
Device 5555 can include various components that are shared between its receiver and transmitter, but this is not necessarily so. It can utilize various UWB frequency hopping techniques known in the art.
Device 5555 is capable of exchanging information with ultra wide band devices that belong to a first group or to a second group of ultra wide band (UWB) devices. The first group of UWB devices can be equivalent to first network 10 or to parent network 5100. The second group of UWB devices can be equivalent to second network 20, to child network 5200 or to an neighbor network (not shown).
In order to exchange information device 5555 includes an UWB transmitter 5551 and an UWB receiver 5559. The receiver 5559 is adapted receive information from at least one device of a first group of ultra wide band devices, using a first frequency hopping sequence. Conveniently, the receiver 5559 is also adapted to receive information from at least one device of the first group of ultra wide band devices, using the first frequency hopping sequence during at least one time period and to receive information from at least one device of a second group of ultra wide band devices, using a second frequency hopping sequence, during at least one other time period.
The transmitter 5551 is adapted to transmit information to at least one device of the first group of ultra wide band devices, using the first frequency hopping sequence during at least one time period and further adapted to transmit information to at least one device of a second group of ultra wide band devices, using a second frequency hopping sequence, during at least one other time period. Conveniently, the transmitted is also adapted to transmit information to at least one device of a first group of ultra wide band devices, using a first frequency hopping sequence.
The device 5555 can manage the access of device of the first and/or second group of UWB devices. Additionally or alternatively, device 5555 can also participate in a distributed media access control scheme in order to control the transmission of devices that belong to the first and/or second group of devices.
Conveniently, device 5555 belongs to the first and second groups of devices. Conveniently, device 5555 only belongs to the second group of devices.
Conveniently, the second frequency hopping sequence is substantially a delayed first frequency hopping sequence. Conveniently, the first and second frequency sequences include hopping between frequencies that belong to the same frequency band group.
Conveniently, device 5555 is further adapted to transmit information representative of the first and second frequency hopping sequences prior to a utilization of the first and second frequency hopping sequences.
Conveniently, device 5555 is adapted to perform a frequency hopping between a transmission of each symbol. Conveniently, the second frequency hopping sequence is substantially a delayed first frequency hopping sequence and the delay is a multiple integer of a inter-symbol period. Conveniently, the second frequency hopping sequence is substantially a delayed first frequency hopping sequence and wherein the delay is fraction of an inter-symbol period.
Conveniently, device 5555 is further adapted to synchronize between the first and second frequency hopping sequences. Conveniently, the at least one time period comprises a first set of time periods and the at least one other time period comprises a second set of time periods. Conveniently, each time period of the first set is followed by a time period of the second set.
According to an embodiment of any of the mentioned above schemes can be applied by two networks that include at least one relaying device for relaying information between at least one device of the first network and at least one device of the second network. By applying the frequency hopping scheme both networks can operate substantially seamlessly while the relaying device can exchange information, during at least one time period, with devices of the first network and exchange information, with device of the second network, during at least one other time period. Whereas at least some of the information exchange includes relaying information.
It will be apparent to those skilled in the art that the disclosed subject matter may be modified in numerous ways and may assume many embodiments other then the preferred form specifically set out and described above. It is noted that each of the mentioned above circuitries can be applied by hardware, software, middleware or a combination of the above. The mentioned above methods can be stored in a computer readable medium, such as but not limited to tapes, disks, diskettes, compact discs, and other optical and/or magnetic medium.
Accordingly, the above disclosed subject matter is to be considered illustrative and not restrictive, and to the maximum extent allowed by law, it is intended by the appended claims to cover all such modifications and other embodiments, which fall within the true spirit and scope of the present invention.
The scope of the invention is to be determined by the broadest permissible interpretation of the following claims and their equivalents rather then the foregoing detailed description.

Claims

1. A method for ultra wide band transmission, the method comprises: (a) allowing a first group of ultra wide band devices to exchange information using a first frequency hopping sequence; and (b) allowing at least one certain device that is responsive to at least one transmission of information from a device of the first group to exchange information using the first frequency hopping sequence during at least one time period and allowing devices that belong to the second group to exchange information using a second frequency hopping sequence during at least one other time period.

2. The method of claim 1 wherein the at least one certain device belongs to the first and second groups of devices.

3. The method of claim 1 wherein the at least one certain device only belongs to the second group of devices.

4. The method of claim 1 wherein the second frequency hopping sequence is substantially a delayed first frequency hopping sequence.

5. The method of claim 1 wherein the first and second frequency sequences include hopping between frequencies that belong to the same frequency band group.

6. The method of claim 1 further comprising controlling the exchange of information between members of the second group by the certain device.

7. The method of claim 1 further comprising controlling the exchange of information between members of the second group by utilizing a distributed media access control scheme.

8. The method of claim 1 further comprising transmitting information representative of the first and second frequency hopping sequences prior to utilizing the first and second frequency hopping sequences.

9. The method of claim 1 wherein the first frequency hopping sequence comprises performing a frequency hopping between a transmission of each symbol.

10. The method of claim 9 wherein the second frequency hopping sequence is substantially a delayed first frequency hopping sequence and wherein the delay is a multiple integer of a inter-symbol period.

11. The method of claim 9 wherein the second frequency hopping sequence is substantially a delayed first frequency hopping sequence and wherein the delay is fraction of an inter-symbol period.

12. The method of claim 9 further comprising repeating stage (b).

13. The method of claim 9 further comprising synchronizing between the first and second frequency hopping sequences.

14. The method of claim 9 wherein the at least one time period comprises a first set of time periods and the at least one other time period comprises a second set of time periods.

15. The method of claim 14 wherein each time period of the first set is followed by a time period of the second set.

16. An ultra wide band device that comprises: a receiver adapted to receive information from at least one device of a first group of ultra wide band devices, using a first frequency hopping sequence; and a transmitter, adapted to transmit information to at least one device of the first group of ultra wide band devices, using the first frequency hopping sequence during at least one time period and further adapted to transmit information to at least one device of a second group of ultra wide band devices, using a second frequency hopping sequence, during at least one other time period.

17. The device of claim 16 wherein the device belongs to the first and second groups of devices.

18. The device of claim 16 wherein the device only belongs to the second group of devices.

19. The device of claim 16 wherein the second frequency hopping sequence is substantially a delayed first frequency hopping sequence.

20. The device of claim 16 wherein the first and second frequency sequences include hopping between frequencies that belong to the same frequency band group.

21. The device of claim 16 further adapted to control an exchange of information between devices of the second group.

22. The device of claim 16 further adapted to participate in a distributed media access control scheme for controlling an exchange of information between members of the second group.

23. The device of claim 16 further adapted to transmit information representative of the first and second frequency hopping sequences prior to a utilization of the first and second frequency hopping sequences.

24. The device of claim 16 adapted to perform a frequency hopping between a transmission of each symbol.

25. The device of claim 24 wherein the second frequency hopping sequence is substantially a delayed first frequency hopping sequence and wherein the delay is a multiple integer of a inter-symbol period.

26. The device of claim 24 wherein the second frequency hopping sequence is substantially a delayed first frequency hopping sequence and wherein the delay is fraction of an inter-symbol period.

27. The device of claim 16 further adapted to synchronize between the first and second frequency hopping sequences.

28. The device of claim 16 wherein the at least one time period comprises a first set of time periods and the at least one other time period comprises a second set of time periods.

29. The device of claim 16 wherein each time period of the first set is followed by a time period of the second set.

30. The method of claim 1 further comprising relaying information, by a certain device, between a device of the first group and a device of the second group.

31. The device of claim 16 further adapted to relay information between a device of the first group and a device of the second group.

32. A computer readable medium having code embodied therein for causing an electronic device to perform the stages of: (a) allowing a first group of ultra wide band devices to exchange information using a first frequency hopping sequence; and (b) allowing at least one certain device that is responsive to at least one transmission of information from a device of the first group to exchange information using the first frequency hopping sequence during at least one time period and allowing devices that belong to the second group to exchange information using a second frequency hopping sequence during at least one other time period.